AS3600 shear dogs breakfast 1

[ASE2020]

Has anybody sorted it out yet? See thread744-447856
I must say the guidance on links in walls is a maze of confusion also, and I've only started reading!
Is it time for Australia to adopt Eurocodes.... the development of Australian Standards seems to be under-resourced. How can a standard be published with so many inherent problems? This could be dangerous.

 

[rapt]

There is nothing to sort out on the difference between the general and Simplified methods!

 

[human909]

Is it time for Australia to adopt Eurocodes....

It is absurd how many Australian standards we have for things that foreign (European) standards are usually superior in most respects. It extends well beyond engineering codes, everything from car safety crash testing and bicycle helmet testing to camping stoves. For a country as small as Australia it really makes so little sense. Given the mediocre state of AU structural codes I don't see many good arguments for keeping them beyond those of vested interests.

 

[IDS]

I'm not sure that a switch to Eurocodes would fix more problems than it solved. For instance see the results below (from 2015) of the prediction of the shear capacity of a deep slab, and compare Eurocode with AS 3600 (2009), and Canadian/AASHTO code values:

Also see the ACI Structural Journal of July this year for a more recent paper (very similar results): Shear Behavior of Thick Slabs, by Michael P. Collins, Phillip T. Quach, and Evan C. Bentz

rapt - It doesn't sound like there is nothing to resolve from the discussion in the linked thread in the OP. Is there another thread where the differences are resolved?

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[rapt]

IDS,

I explained the difference in the results between the General and Simplified methods in my last post on it in that thread.

My preference (I obviously lost the argument) would not to have had the simplified method as it makes assumptions about what the designer is going to do in his detailing. But it was in the Canadian Code implementation of MCFT and there are also versions of it in also the AASHTO implementation and also the Model Code. So it was included in the Australian code as it gave designers a way to avoid using a couple of relatively simple equations based on, strain = (M / d + V) / Ast fsy, in some simple cases and replacing them with a couple of constants. So we can blame the Canadians for it!

It cannot be used in many cases e.g. PT and they are the cases where the formula is more complicated. The general equation for RC is no more complicated than the old code method so I would ignore the simplified method and use the General Method as it applies in all cases, so there is no decision to make and it is no more complicated for designers than what they are used to. That is what we have done in RAPT.

Interestingly, it is very likely Eurocode will move towards MCFT in its next incarnation, so AS3600 is actually more advanced than Eurocode in this. If people complaining about AS3600 actually looked into Eurocode in detail, they would be making the same comments about problems in it. In Eurocode, minimum reinforcement, ductility, shear and several other areas have major problems.

Yes, there are problems in the ASA3600 code at the moment and there will be an amendment, but it has to go to public review so it will take a while to be included. But the basic method in the code is correct and in my opinion is an improvement on the old code methodology. In this instance the new shear provisions are much more logical and are are an improvement on a 70 year old very limited method from the old codes and it would be sensible for engineers to take a positive approach and look into it in more detail and understand the method rather than just whinging about change and some mistakes, the reasons for which I am not at liberty to go into. By now, everyone knows it comes from MCFT so read up on the background. There are a lot of papers freely available on it on google, normally by Michael Collins and/or Evan Bentz. One in ACI Structural Journal in July/August in 2006 "Simplified Modified Compression Field Theory ................" is a very good description of the evolution of MCFT.